The study was carried out in Glasgow City Centre with a total of
11 colocation exercises to evaluate agreement between samplers; and
8 mobile monitoring exercises to evaluate potential concentration
gradients between 0.80 m and 1.68 m. All monitoring exercises were
carried out between February 2014 and September 2014. In order to
maximise the range of conditions captured (e.g. traffic and weather
conditions), the monitoring exercises were carried out over 6
weekdays (2 x Fridays) and 2 weekend days.

Contour plots of pollutant concentrations throughout the mobile
monitoring route were produced in order to help analyse the spatial
distribution of pollutants and assess the influences of local
factors, such as traffic density.

The findings of the Glasgow study demonstrated the complexity of
ambient air quality within the urban environment and the challenges
of monitoring a range of important pollutants within such an
environment. Within a limited duration exercise, the study provided
valuable insights into not only spatial variations of key air
pollutants in Glasgow City centre but also the influence of
exposure height on the concentrations observed. In addition, the
study also helped to elucidate correlations between observed
concentrations of different pollutants at different exposure
heights and also provide useful information regarding the
application of mobile monitoring and the application of personal
sampler/ sensor technology for assessing human exposure to air
pollutants in an urban environment.

In brief summary, the study identified that spatial and temporal
variations in pollutant concentrations in Glasgow City centre are
generally species specific and can also be influenced by a wide
range of other environmental parameters, such as the proximity to
pollution sources. Whilst a large number of initial conclusions
have been drawn, several of the findings are considered to merit
further attention. These were:

It was identified that consistently higher average
concentrations of PM
2.5 (42% higher) and PM
10 (47-63% higher) were recorded by the mobile
monitoring trolley when monitoring along the study route than
those reported at the fixed Glasgow Kerbside
AURN
monitoring site.

Average concentrations of PM
10 were shown to be consistently higher (up to 12.6%
higher) at 0.80 m than at 1.68 m throughout the mobile monitoring
trolley study route. This finding is significant, as it appears
to indicate that in the urban environment children may be exposed
to higher concentrations of PM
10 on average than adults. However, this relationship
was not observed for concentrations of PM
2.5.

For NO
2, at lower ambient concentrations, no consistent
influence of exposure height was identified on observed
concentrations. However, at higher ambient concentrations, such
as that may be observed in close proximity to busy road
junctions, significantly higher concentrations were observed at
adult breathing height (1.68 m) than at child breathing height
(0.80 m).

Visualisation of pollutant concentrations monitored through
the application of the mobile monitoring trolley demonstrated
potential for the identification or confirmation of pollutant
hotspots within urban environments. Through the application of
such a mobile monitoring 'screening' approach, authorities may be
able to confirm the presence and extent of pollution hotspots,
and thus investigate, design and implement appropriate mitigation
measures.

Overall, the study provided valuable insights into spatial
(vertical and horizontal) variations of concentrations of key air
pollutants in Glasgow City centre. The study has generated numerous
interesting findings which with further research could help to
inform and guide future air quality research and policy in
Scotland.